Granular resins are supplied in the forms of emulsions, microgels, non-aqueous dispersions and powder resins, and have been watched with keen interest in paint industries, as an eminent approach to the ideal aqueous paints, high solids paints and powder paints which will fulfill the requirements of economization of natural resources, energy-saving and conservation of good surroundings.
They are used each singularly or in combination form with other soluble type resins and are believed to act as a binder, a rheology regulator or a polymer filler. Thus, a high quality film can be obtained therewith.
However, when the granular resin is used alone, it is unable to get a uniform or excellent film and the resulted film has a serious drawback of being deficient in film appearance. Even when the granular resin is combined with a soluble type resin, there is a case wherein the viscosity of the combined system is greatly increased as compared with that of the soluble type resin alone due to the considerable interaction between the surfaces of granules and soluble type resin. Therefore, a great care is often required in the actual use of such combined resins.
The inventors have previously found that the composite resin particles, each of which comprises a granular body portion of a crosslinked polymer and a number of linear polymer chains, a part of the respective linear polymer chain penetrating into said body portion and the remaining part extending outwardly therefrom, are free from the drawbacks of heretofore proposed coating use resins, and are able to use either singularly or in the combination form with any other resins customarily used in paint industry, to give excellent coating compositions with good application characteristics and storage stability, capable of resulting a uniform film with excellent appearance, and on the basis of these findings have applied a patent (Japanese Patent Application No. 267019/84).
The present invention is on the same line with that of the prior patent application and concerns a development thereof. Thus, a principal object of the invention to provide novel composite resin particles which can be used either singularly or in the combination with other coating use resins in the known coating compositions as well as in novel coating compositions, which are excellent in application characteristics, storage stability, electrophoresis and the like and capable of resulting uniform coatings with excellent appearance and especially in gloss and distinctness. Additional object of the invention is to provide a method for the preparation of said composite resin particles. Further object of the invention is to provide a resinous composition containing said novel composite resin particles and being useful as resinous vehicle of coating compositions.